In a class, the number of boys who can swim is one more than the number of girls who can swim. The number of girls who cannot swim is one more than the number of boys that cannot swim. The difference between number of boys who can swim and number of girls who cannot swim is two. Then which of the following is true?

Let say,

number of boys who can swim is a and who cant is b.

And number of girls who can swim is c and who cant is d.

The number of boys who can swim is one more than the number of girls who can swim a = c+1

The number of girls who cannot swim is one more than the number of boys that cannot swim => d = b+1

The difference between number of boys who can swim and number of girls who cannot swim is two => a - d = 2